Struct WriteContext 

struct WriteContext {
    rx: Receiver<(ReadStatData, WriteConfig, usize)>,
    reader: JoinHandle<Result<(), ReadStatError>>,
    wc: WriteConfig,
    input_path: PathBuf,
    var_count: i32,
    vars: Arc<BTreeMap<i32, ReadStatVarMetadata>>,
    schema: Arc<Schema>,
}

State shared by every write strategy in run_data.

Owns the channel receiver and the reader-thread handle so it can move into whichever strategy runs. The metadata fields (var_count, vars, schema) and input_path are used to emit a valid empty file when the input has zero rows; the SQL path ignores them.

Fields

rx: Receiver<(ReadStatData, WriteConfig, usize)>

Receiver of parsed chunks from the reader thread.

reader: JoinHandle<Result<(), ReadStatError>>

Handle to the reader thread, joined before output is finalized.

wc: WriteConfig

Output configuration (path, format, compression).

input_path: PathBuf

Input file path, for the write summary.

var_count: i32

Variable count, for emitting an empty file on zero rows.

vars: Arc<BTreeMap<i32, ReadStatVarMetadata>>

Variable metadata, for emitting an empty file on zero rows.

schema: Arc<Schema>

Arrow schema, for emitting an empty file on zero rows.